Multifurcating heat exchanger with independent baffles

ABSTRACT

A heat exchanger includes a core defining a first passageway for a first fluid flow and a second passageway for a second fluid flow. The core includes an assembly of a plurality of unit cells coupled together. Each unit cell defines a first passageway portion within an interior volume and a second passageway portion at an exterior surface. Each unit cell includes a plurality of first openings into the interior volume and forms the second passageway in volumes between the plurality of unit cells. The assembly is shaped to combine and divide the first fluid in the first passageway portion and combine and divide the second fluid in the second passageway portion during exchange of heat between the first fluid and the second fluid. Each second passageway portion receives the second fluid from three other second passageway portions. The heat exchanger further includes at least one baffle in at least one of the first passageway or the second passageway to route the first fluid flow independently from the second fluid flow.

BACKGROUND

The present disclosure relates generally to heat exchangers and, morespecifically, heat exchangers including unit cells forming furcatingflow passageways and a baffle design that allows for independentbaffling of each fluid domain.

Some heat exchangers utilize heat transfer fluids that flow through theheat exchangers and transfer heat. A heat transfer efficiency of theheat exchangers is determined, at least in part, by the flow of the heattransfer fluids through the heat exchangers. As the heat transfer fluidsflow through the heat exchangers, the heat transfer fluids tend toestablish a boundary layer which increases thermal resistance andreduces the heat transfer efficiency of the heat exchangers. The heattransfer efficiency of the heat exchangers is also affected bycharacteristics of the heat exchanger such as material properties,surface areas, flow configurations, pressure drops, and resistivity tothermal exchange. Improving any of these characteristics allows the heatexchanger to have an increased heat transfer efficiency.

Some systems or applications require heat exchangers to fit within aspecified system volume and weigh less than a specified weight. Reducingthe size of the heat exchangers to meet system requirements affects thecharacteristics that determine heat transfer efficiency. Some heatexchangers are not properly shaped to fit within the systems, whichresults in ineffective use of space and/or wasted volume. Some heatexchangers are formed to meet system requirements using fabricationtechniques that require multiple joints, such as brazed and weldedjoints. Such joints may deteriorate over time, thereby decreasing aservice life of the heat exchangers.

BRIEF DESCRIPTION

According to one example, a heat exchanger comprises a core. The coredefines a first passageway configured for a first fluid to flow throughand a second passageway configured for a second fluid to flow through.The core comprises an assembly comprised of a plurality of unit cellscoupled together. Each unit cell of the assembly defines a firstpassageway portion within an interior volume of each unit cell and asecond passageway portion at an exterior surface of each unit cell. Eachunit cell includes a plurality of first openings into the interiorvolume for flow of the first fluid through the first passageway portion.The assembly forms the second passageway in volumes between theplurality of unit cells coupled together. The assembly is shaped tocombine and divide the first fluid in the first passageway portion ineach unit cell and to combine and divide the second fluid in the secondpassageway portion of each unit cell during exchange of heat between thefirst fluid and the second fluid. Each second passageway portionreceives the second fluid from three other second passageway portions.The heat exchanger further comprises at least one baffle in at least oneof the first passageway or the second passageway configured to route theflow of first fluid independently from the flow of second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a schematic sectional view of an exemplary heat exchanger;

FIG. 2 is a schematic view of a portion of the heat exchanger shown inFIG. 1;

FIG. 3 is a schematic isometric view of a unit cell of the heatexchanger shown in FIG. 1;

FIG. 4 is a schematic side view of a plurality of the unit cells shownin FIG. 3;

FIG. 5 is a schematic side view of an exemplary unit cell for use in theheat exchanger shown in FIG. 1

FIG. 6 is a schematic view of fluid flow through a plurality of the unitcells shown in FIG. 5;

FIG. 7 is a schematic view of a plurality of exemplary flow passagesadjacent a casing of the heat exchanger shown in FIG. 1;

FIG. 8 is a schematic view of a plurality of exemplary flowconfigurations of the heat exchanger shown in FIG. 1;

FIG. 9 is a schematic view of a hybrid counter-flow configuration of theheat exchanger shown in FIG. 1;

FIG. 10 is a schematic view of a hybrid parallel flow configuration ofthe heat exchanger shown in FIG. 1;

FIG. 11 is a schematic perspective view of an exemplary heat exchangercore;

FIG. 12 is a schematic side view of the exemplary heat exchanger core ofFIG. 11;

FIG. 13 is a schematic end view of the exemplary heat exchanger core ofFIG. 11; and

FIG. 14 is a schematic view of the and the first and second flowdomains.

DETAILED DESCRIPTION

In the following specification and the claims, reference will be made toa number of terms, which shall be defined to have the followingmeanings.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “substantially,” and “approximately,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.

As used herein, the terms “axial” and “axially” refer to directions andorientations that extend substantially parallel to a centerline of theheat exchanger. Moreover, the terms “radial” and “radially” refer todirections and orientations that extend substantially perpendicular tothe centerline of the heat exchanger. In addition, as used herein, theterms “circumferential” and “circumferentially” refer to directions andorientations that extend arcuately about the centerline of the heatexchanger. It should also be appreciated that the term “fluid” as usedherein includes any medium or material that flows, including, but notlimited to, air, gas, liquid, and steam.

The systems and methods described herein include a core that enablesheat exchangers to have different shapes, sizes, and flowconfigurations. The core includes a plurality of unit cells. The unitcells define passageways for at least two different heat exchange fluidssuch that the fluids combine and divide in close proximity separatedonly by a sidewall of the unit cell. In some embodiments, each unit cellis configured to receive flows of heat exchange fluid from at leastthree other unit cells such that the flows combine into a single flow.In addition, each unit cell forms a trifurcated passageway portion suchthat the flow divides and is discharged into at least three other unitcells. As a result, the thermal boundary layers of the heat exchangefluids are reduced and the heat exchange fluids more efficientlytransfer heat through the sidewalls of the unit cells in comparison toheat exchange fluids in known heat exchangers. Moreover, the heatexchangers described herein include multiple arrangements and flowconfigurations to meet overall system requirements and have increasedefficiency.

FIG. 1 is a sectional view of an exemplary heat exchanger 100. FIG. 2 isa partially schematic view of a portion of heat exchanger 100. Heatexchanger 100 includes a core 102, a redirection portion 103, a manifoldportion 104, and a casing 106. Each of manifold portion 104, core 102,and redirection portion 103 includes a plurality of unit cells 108defining a first passageway 110 for a first fluid 112 to flow throughand a second passageway 114 for a second fluid 116 to flow through. Inredirection portion 103, first fluid 112 and second fluid 116 areredirected by unit cells 108. Specifically, first fluid 112 and secondfluid 116 are turned approximately 180. degree. in redirection portion103. In alternative embodiments, heat exchanger 100 has anyconfiguration that enables heat exchanger 100 to operate as describedherein. For example, in some embodiments, at least a portion of firstfluid 112 and/or second fluid 116 is replaced with an at least partiallysolid substance configured to accommodate thermal shocks, such as wax,fusible alloy and/or molten salt.

In the exemplary embodiment, manifold portion 104 includes a first inlet118, a second inlet 120, an inlet header 122, an outlet header 124, afirst outlet 126, and a second outlet 128. In alternative embodiments,manifold portion 104 has any configuration that enables heat exchanger100 to operate as described herein. For example, in some embodiments,manifold portion 104 includes a plurality of first inlets 118, secondinlets 120, inlet headers 122, outlet headers 124, first outlets 126,and/or second outlets 128. In further embodiments, heat exchanger 100includes a plurality of manifold portions 104 coupled to core 102.

In the exemplary embodiment, each of inlet header 122 and outlet header124 include a plurality of ports 130 in fluid communication with firstpassageway 110. Inlet header 122 and outlet header 124 change incross-sectional area along the direction of flow of first fluid 112 toaccommodate the differing volume of first fluid 112 in inlet header 122and outlet header 124 due to first fluid 112 flowing through ports 130.Specifically, inlet header 122 tapers in cross-sectional area from amaximum cross-sectional area adjacent first inlet 118 to a minimumcross-sectional area adjacent a distal end of inlet header 122. Outletheader 124 increases in cross-sectional area from a minimumcross-sectional area adjacent a distal end of outlet header 124 to amaximum cross-sectional area adjacent first outlet 126. Ports 130 aresubstantially bell-shaped to facilitate smooth fluid flow through ports130 and to minimize irreversible flow losses. In alternativeembodiments, heat exchanger 100 includes any inlet header 122 and outletheader 124 that enables heat exchanger 100 to operate as describedherein. For example, in some embodiments, heat exchanger 100 includes aplurality of inlet headers 122 and outlet headers 124. In furtherembodiments, at least one inlet header 122 and/or outlet header 124 iscoupled to second passageway 114.

In the exemplary embodiment, core 102 further includes an inlet plenum134 and an outlet plenum 136. Inlet plenum 134 and outlet plenum 136 arein fluid communication with second passageway 114. Inlet plenum 134 iscoupled to second inlet 120 and outlet plenum 136 is coupled to secondoutlet 128. Inlet plenum 134 and outlet plenum 136 are adjacent inletheader 122 and outlet header 124 to facilitate first fluid 112 andsecond fluid 116 exchanging heat as first fluid 112 and second fluid 116flow into and out of core 102. Moreover, a plurality of conduits 125 arecoupled to inlet header 122 and outlet header 124 and extend throughinlet plenum 134 and outlet plenum 136. In alternative embodiments, heatexchanger 100 includes any inlet plenums 134 and outlet plenums 136 thatenable heat exchanger 100 to operate as described herein.

Also, in the exemplary embodiment, core 102 is manufactured using anadditive manufacturing process. An additive manufacturing process allowscore 102 to have complex geometries while limiting the number of jointsof core 102. In alternative embodiments, core 102 is formed in anymanner that enables heat exchanger 100 to operate as described herein.

During operation of heat exchanger 100, first fluid 112 flows into inletheader 122 through first inlet 118 and is distributed into firstpassageway 110 through ports 130. First fluid 112 in first passageway110 is directed through core 102, redirection portion 103, and manifoldportion 104. After flowing through first passageway 110, first fluid 112flows through ports 130 into outlet header 124 and is discharged fromheat exchanger 100 through first outlet 126. Second fluid 116 flows intoinlet plenum 134 through second inlet 120 and is distributed into secondpassageway 114. Second fluid 116 in first passageway 114 is directedthrough core 102, redirection portion 103, and manifold portion 104.After flowing through second passageway 114, second fluid 116 flows intooutlet plenum 136 where second fluid 116 is discharged from heatexchanger 100 through second outlet 128.

In alternative embodiments, heat exchanger 100 includes any passagewaysthat enable heat exchanger 100 to operate as described herein. Forexample, in some embodiments, heat exchanger 100 includes at least onebypass passageway (not shown) to enable first fluid 112 and/or secondfluid 116 to bypass at least a portion of first passageway 110 and/orsecond passageway 114. The bypass passageway (not shown) extends throughany portions of heat exchanger 100, e.g., through core 102, redirectionportion 103, manifold portion 104, and/or along an external periphery ofheat exchanger 100. As a result, the bypass passageway (not shown)facilitates management of pressure drop due to excess amounts of firstfluid 112 and/or second fluid 116.

Moreover, in the exemplary embodiment, core 102 is configured such thatfirst fluid 112 and second fluid 116 exchange heat as first fluid 112and second fluid 116 flow through core 102, redirection portion 103, andmanifold portion 104. For example, as shown in FIG. 2, first fluid 112and second fluid 116 exchange heat through sidewalls of unit cells 108as first fluid 112 and second fluid 116 flow through portions of firstpassageway 110 and second passageway 114 defined by unit cells 108. Aswill be described in more detail below, unit cells 108 define portionsof first passageway 110 and second passageway 114 where first fluid 112and second fluid 116 combine and divide to disrupt thermal boundarylayers in first fluid 112 and second fluid 116. In the exemplaryembodiment, unit cells 108 are aligned and coupled together such thatcore 102 is substantially symmetrical, which facilitates multiple flowconfigurations of heat exchanger 100. For example, in the illustratedembodiment, core 102 has a diamond shape. In alternative embodiments,core 102 has any configuration that enables heat exchanger 100 tooperate as described herein.

In some embodiments, core 102 is divided up into independent zones. Unitcells 108 facilitate sectioning and/or segmenting core 102 into theindependent zones. In further embodiments, heat exchanger 100 includes aplurality of discrete cores 102. The repeating geometric shapes of unitcells 108 facilitate core 102 coupling to other cores 102 in multipledifferent configurations. In some embodiments, heat exchanger 100includes a segment (not shown) linking separate cores 102 such that aportion of fluid flows through the segment between cores 102.

FIG. 3 is a schematic isometric view of unit cell 108. FIG. 4 is aschematic side view of a plurality of unit cells 108. In someembodiments, core 102 includes some unit cells 108 that differ in someaspects from unit cells 108 shown in FIGS. 3 and 4. In the exemplaryembodiment, each unit cell 108 includes a sidewall 138 defining aplurality of unit cell inlets 140, a plurality of unit cell outlets 142,an interior surface 144, and an exterior surface 146. First fluid 112flows into unit cell 108 through unit cell inlets 140, contacts interiorsurface 144, and flows out of unit cell 108 through unit cell outlets142. Second fluid 116 flows past unit cell 108 such that second fluid116 contacts exterior surface 146. In the illustrated embodiment, eachunit cell 108 has three unit cell inlets 140 and three unit cell outlets142. In alternative embodiments, unit cell 108 has any unit cell inlets140 and unit cell outlets 142 that enable heat exchanger 100 to operateas described herein.

Also, in the exemplary embodiment, each unit cell 108 forms a firstpassageway portion 148 of first passageway 110 and a second passagewayportion 150 of second passageway 114. First passageway portion 148 andsecond passageway portion 150 are configured for first fluid 112 andsecond fluid 116 to exchange thermal energy through sidewall 138. Inoperation, first fluid 112 flows into first passageway portion 148 fromother first passageway portions 148 associated with other unit cells108. First passageway portion 148 furcates such that first fluid 112flows out of first passageway portion 148 towards further firstpassageway portions 148. In particular, first passageway portion 148trifurcates such that first fluid 112 flows into three flow pathstowards three different first passageway portions 148. Second fluid 116flows into second passageway portion 150 from other second passagewayportions 150. Second passageway portion 150 furcates such that secondfluid 116 flows out of second passageway portion 150 towards furthersecond passageway portions 150. In particular first passageway portion148 trifurcates such that second fluid 116 flows into three flow pathstowards three different second passageway portions 150. First passagewayportion 148 and second passageway portion 150 furcate at anapproximately 90 degree angle. In alternative embodiments, firstpassageway portion 148 and second passageway portion 150 furcate at anyangles that enable heat exchanger 100 to operate as described herein.

The furcated shapes of first passageway portion 148 and secondpassageway portion 150 provide for additional surface area to facilitateheat exchange between first fluid 112 and second fluid 116. Moreover,the furcation of unit cells 108 reduces and/or inhibits the formation ofthermal boundary layers in first fluid 112 and second fluid 116. Forexample, thermal and momentum boundary layers are broken up each timefirst fluid 112 and second fluid 116 are redirected due to unit cells108 furcating. Moreover, the repeated furcation in unit cells 108inhibit first fluid 112 and second fluid 116 from establishingsignificant thermal and momentum boundary layers. In alternativeembodiments, first passageway portion 148 and second passageway portion150 have any configuration that enables heat exchanger 100 to operate asdescribed herein.

In addition, in the exemplary embodiment, first passageway portion 148has a first hydraulic diameter 152 and second passageway portion 150 hasa second hydraulic diameter 154. First hydraulic diameter 152 and secondhydraulic diameter 154 are determined based on flow requirements, suchas flow rate, pressure drop, and heat transfer, and/or volumerequirements for heat exchanger 100. Unit cell 108 forms firstpassageway portion 148 such that first hydraulic diameter 152 isapproximately equal to the width of unit cell inlet 140. Secondpassageway portion 150 is formed by multiple unit cells 108.Accordingly, unit cell 108 spans only a portion of second hydraulicdiameter 154. In the illustrated embodiment, unit cell 108 spansapproximately half of second hydraulic diameter 154. Moreover, in theexemplary embodiment, first hydraulic diameter 152 is approximatelyequal to second hydraulic diameter 154. In alternative embodiments,first passageway portion 148 and second passageway portion 150 have anyhydraulic diameters that enable heat exchanger 100 to operate asdescribed herein. For example, in some embodiments, first hydraulicdiameter 152 and second hydraulic diameter 154 are different from eachother. In further embodiments, first hydraulic diameter 152 is greaterthan second hydraulic diameter 154 such that a ratio of first hydraulicdiameter 152 to second hydraulic diameter 154 is at least .

Moreover, in the exemplary embodiment, first passageway portion 148 andsecond passageway portion 150 have a square cross-sectional shape. Inalternative embodiments, first passageway portion 148 and secondpassageway portion 150 have any cross-sectional shape that enables heatexchanger 100 to operate as described herein. For example, in someembodiments, first passageway portion 148 and/or second passagewayportion 150 have any of the following cross-sectional shapes, withoutlimitation: rectangular, diamond, circular, and triangular. Moreover, insome embodiments, first passageway portion 148 and/or second passagewayportion 150 include any of the following, without limitation: a fin, asurface having engineered roughness, a surface roughened bymanufacturing process, any other heat transfer enhancement, andcombinations thereof.

In the exemplary embodiment, the shape and size of unit cells 108 isdetermined based at least in part on any of the following, withoutlimitation: surface area, pressure drop, compactness of core 102, andfluid flow. In the exemplary embodiment, unit cells 108 havesubstantially the same shape. In particular, unit cells 108 have apartially cuboid shape. In alternative embodiments, core 102 includesany unit cells 108 that enable heat exchanger 100 to operate asdescribed herein. In some embodiments, core 102 includes unit cells 108that differ in configuration from each other. In further embodiments,the shape of unit cells 108 at least partially conforms to a shape ofcore 102. For example, in some embodiments, unit cells 108 are at leastpartially curved to align with an annular shape of core 102.

In some embodiments, at least a portion of unit cells 108 are flexibleto facilitate unit cells 108 shifting in response to characteristics offirst fluid 112 and/or second fluid 116 such as pressure, flow rate,volume, and density. For example, in some embodiments, sidewalls 138 areflexible and adjust to attenuate fluid surge. In further embodiments,unit cells 108 are flexible such that first fluid 112 causes firstpassageway 110 to expand and at least partially propel second fluid 116through second passageway 114. In the exemplary embodiment, sidewalls138 of unit cells 108 are substantially rigid. In alternativeembodiments, unit cells 108 have any amount of flexibility that enablesheat exchanger 100 to operate as described herein.

FIG. 5 is a schematic side view of a unit cell 156 for use in the heatexchanger 100. FIG. 6 is a schematic view of fluid flow through aplurality of unit cells 156. Unit cell 156 includes a sidewall 158 atleast partially defining first passageway portion 148 and secondpassageway portion 150. First passageway portion 148 has first hydraulicdiameter 152 and second passageway portion 150 has second hydraulicdiameter 154. Unit cells 156 are configured such that first hydraulicdiameter 152 is different than second hydraulic diameter 154. Inaddition, sidewall 158 is at least partially curved such that firstpassageway portion 148 and second passageway portion 150 form blendedflow passageways. In particular, the edges of sidewall 158 are blendedto facilitate smooth fluid flow. The hydrodynamic shape of firstpassageway portion 148 and second passageway portion 150 reducespressure drop due to changes in direction of first fluid 112 and secondfluid 116. In alternative embodiments, core 102 includes any unit cells156 that enable heat exchanger 100 to operate as described herein. Insome embodiments, unit cell 156 incorporates minimal surfaces tofacilitate blending of unit cell 156. For example, in some embodiments,unit cell 156 maintains a constant mass and reduced stress to increasestructural and pressure capabilities. In further embodiments, structuraland pressure capability remain constant and the mass is reduced.

With particular reference to FIG. 6, an example flow of first fluid 112and second fluid 116 through a plurality of unit cells 108 is described.FIG. 6 includes an X-axis, a Y-axis, and a Z-axis for referencethroughout the following description. Arrows 160 indicate the flowdirection of first fluid 112 and arrows 162 indicate the flow directionof second fluid 116. Arrows 160 and arrows 162 extend in theX-direction, the Y-direction, and the Z-direction. Notably, arrows 160extending in the Z-direction point into the drawing sheet away from theviewer and arrows 162 extending in the Z-direction point out of thedrawing sheet towards the viewer.

Unit cells 108 are coupled in flow communication such that each firstpassageway portion 148 receives first fluid 112 from three other firstpassageway portions 148 and each second passageway portion 150 receivessecond fluid 116 from three other second passageway portions 150. Inaddition, each first passageway portion 148 directs first fluid 112towards three different first passageway portions 148 and each secondpassageway portion 150 directs second fluid 116 toward three differentsecond passageway portions 150. Accordingly, first fluid 112 and secondfluid 116 flow in at least partially counter-flow directions. Inalternate embodiments, first fluid 112 and second fluid 116 flow in anydirections that enable heat exchanger 100 to operate as describedherein. For example, in some embodiments, heat exchanger 100 isconfigured such that first fluid 112 and second fluid 116 flow incounter-flow directions, parallel-flow directions, cross-flowdirections, and hybrids thereof.

FIG. 7 is a schematic view of flow passages 166 adjacent casing 106 ofheat exchanger 100 (shown in FIG. 1). Flow passages 166 are formed byperipheral unit cells 168 such that fluid 170 flows through flowpassages 166. Fluid 170 is one of first fluid 112 (shown in FIG. 1) andsecond fluid 116 (shown in FIG. 1). In alternative embodiments, fluid170 is any fluid that enables heat exchanger 100 to operate as describedherein. In the exemplary embodiment, flow passages 166 are configured todirect fluid 170 away from casing 106 to inhibit fluid 170 becomingtrapped in a stagnant zone 172. Some flow passages 166 include a barrier174 that inhibits fluid 170 entering stagnant zone 172. Some flowpassages 166 include a channel 176 for fluid 170 to flow out of stagnantzone 172. In alternative embodiments, flow passages 166 are configuredin any manner that enables heat exchanger 100 to operate as describedherein. For example, in some embodiments, unit cells 168 are configuredsuch that fluid 170 flows through a geometric flow transition, such asthe 180 degree turn in redirection portion 103 (shown in FIG. 1), whilemaintaining heat exchange throughout at least a portion of the geometricflow transition.

In some embodiments, components of heat exchanger 100, such as core 102,are used in applications not necessarily requiring heat exchange. Forexample, in some embodiments, components of heat exchanger 100 are usedin reactor applications, mass transfer applications, phase-changeapplications, and solid oxide fuel cells (SOFC). In some embodiments ofSOFC systems, unit cells 108 are positioned betweenanode-electrolyte-cathode layers. In some embodiments of phase-changesystems, unit cells 108 include sidewalls 138 having small pores (notshown) and/or engineered surfaces (not shown) to allow fluids to boiland/or condense. In alternative embodiments, heat exchanger 100 is usedfor any applications and/or systems that require movement of fluid.

FIG. 8 is a schematic view of flow configurations of heat exchanger 100.Heat exchanger 100 is configured such that first fluid 112 and secondfluid 116 flow through core 102 in multiple directions. In particular,manifold portion 104 is configured and/or coupled to core 102 indifferent locations such that first fluid 112 and second fluid 116 aredirected through core 102 in different directions. Core 102 does nothave to change shape, size, and/or arrangement of unit cells 108 toaccommodate different locations and configurations of manifold portions104. Moreover, the different configurations of core 102 and manifoldportion 104 enable heat exchanger 100 to meet specific systemrequirements, such as shape, space, and piping requirements. Forexample, in some embodiments, manifold portions 104 are coupled tospecific locations on core 102 that enable heat exchanger 100 to fitdifferent spaces, shapes, and/or piping connections. In furtherembodiments, unit cells 108 are coupled together to form core 102 havinga desired shape and flow configuration. In alternative embodiments, core102 and manifold portion 104 have any configuration that enables heatexchanger 100 to operate as described herein.

In one embodiment, heat exchanger 100 is configured such that firstfluid 112 and second fluid 116 flow through core 102 in a counter-flowconfiguration 200. In counter-flow configuration 200, a first manifoldportion 202 and a second manifold portion 204 are coupled to opposedends of core 102. First manifold portion 202 includes a first fluidinlet 206 and a second fluid outlet 208. Second manifold portion 204includes a first fluid outlet 210 and a second fluid inlet 212. Firstfluid 112 is directed through core 102 from first fluid inlet 206 towardfirst fluid outlet 210 and second fluid 116 is directed through core 102from second fluid inlet 212 toward second fluid outlet 208. As a result,first fluid 112 and second fluid 116 flow through core 102 insubstantially opposed directions.

In another embodiment, heat exchanger 100 is configured such that firstfluid 112 and second fluid 116 flow through core 102 in a parallel-flowconfiguration 214. In parallel-flow configuration 214, a first manifoldportion 216 and a second manifold portion 218 are coupled to opposedends of core 102. First manifold portion 216 includes a first fluidinlet 220 and a second fluid inlet 222. Second manifold portion 218includes a first fluid outlet 224 and a second fluid outlet 226. Firstfluid 112 is directed through core 102 from first fluid inlet 220 towardfirst fluid outlet 224 and second fluid 116 is directed through core 102from second fluid inlet 222 toward second fluid outlet 226. As a result,first fluid 112 and second fluid 116 flow through core 102 insubstantially parallel directions.

In another embodiment, heat exchanger 100 is configured such that firstfluid 112 and second fluid 116 flow through core 102 in a cross-flowconfiguration 228. In cross-flow configuration 228, first manifoldportion 230 and second manifold portion 232 are coupled to opposed endsof core 102. Third manifold portion 234 and fourth manifold portion 236are coupled to sides of core 102. First manifold portion 230 includes afirst fluid inlet 238 and second manifold portion 232 includes a firstfluid outlet 240. Third manifold portion 234 includes a second fluidinlet 242 and fourth manifold portion 236 includes a second fluid outlet244. First fluid 112 is directed through core 102 from first fluid inlet238 towards first fluid outlet 240. Second fluid 116 is directed throughcore 102 from second fluid inlet 242 towards second fluid outlet 244. Asa result, first fluid 112 and second fluid 116 flow through core 102 insubstantially transverse directions. In particular, the flow of firstfluid 112 is substantially perpendicular to the flow of second fluid116.

FIG. 9 is a schematic view of a hybrid counter-flow configuration 300 ofheat exchanger 100. In hybrid counter-flow configuration 300, a firstmanifold portion 302 is coupled to a side of core 102. A second manifoldportion 304 and a third manifold portion 306 are coupled to opposed endsof core 102. First manifold portion 302 includes a first fluid inlet 308and a first header 310. Second manifold portion 304 includes a secondfluid inlet 312, a first fluid outlet 314, a second header 316, and athird header 318. Third manifold portion 306 includes a fourth header320 and a second fluid outlet 322. First fluid 112 is directed throughcore 102 from first fluid inlet 308 and first header 310 towards thirdheader 318 and first fluid outlet 314. First fluid 112 is at leastpartially redirected as first fluid 112 flows through core 102. Secondfluid 116 is directed through core 102 from second fluid inlet 312 andsecond header 316 towards fourth header 320 and second fluid outlet 322.As a result, the flow configurations of first fluid 112 and second fluid116 vary through regions of core 102. In particular, first fluid 112 andsecond fluid 116 flow through a cross-flow region 324, a hybrid flowregion 326, and a counter-flow region 328. In cross-flow region 324,first fluid 112 and second fluid 116 flow in substantially transversedirections. In hybrid flow region 326, the directions of flow of firstfluid 112 and second fluid 116 change in relation to each other suchthat the flows are partially transverse and partially opposed. In hybridflow region 326, a portion of the flows of first fluid 112 and secondfluid 116 are diagonal to each other. In counter-flow region 328, firstfluid 112 and second fluid 116 flow in substantially opposed directions.

FIG. 10 is a schematic view of a hybrid parallel flow configuration 400of heat exchanger 100. In hybrid parallel flow configuration 400, afirst manifold portion 402 is coupled to a side of core 102. A secondmanifold portion 404 and a third manifold portion 406 are coupled toopposed ends of core 102. First manifold portion 402 includes a firstfluid inlet 408 and a first header 410. Second manifold portion 404includes a second fluid outlet 412, a first fluid outlet 414, a secondheader 416, and a third header 418. Third manifold portion 406 includesa fourth header 420 and a second fluid inlet 422. First fluid 112 isdirected through core 102 from first fluid inlet 408 and first header410 towards second header 416 and first fluid outlet 414. First fluid112 is at least partially redirected as first fluid 112 flows throughcore 102. Second fluid 116 is directed through core 102 from secondfluid inlet 422 and fourth header 420 towards third header 418 andsecond fluid outlet 412. As a result, the flow configurations of firstfluid 112 and second fluid 116 vary through regions of core 102. Inparticular, first fluid 112 and second fluid 116 flow through across-flow region 424, a hybrid flow region 426, and a parallel flowregion 428. In cross-flow region 424, first fluid 112 and second fluid116 flow in substantially transverse directions. In hybrid flow region426, the directions of flow of first fluid 112 and second fluid 116change in relation to each other such that the flows are partiallytransverse and partially parallel. In hybrid flow region 426, a portionof the flows of first fluid 112 and second fluid 116 are diagonal toeach other. In parallel flow region 428, first fluid 112 and secondfluid 116 flow in substantially parallel directions.

In alternative embodiments, first fluid 112 and second fluid 116 flowthrough core 102 in any directions that enable heat exchanger 100 tooperate as described herein. For example, in some embodiments, at leastone of first fluid 112 and second fluid 116 is redirected as first fluid112 and/or second fluid 116 flows through core 102. In furtherembodiments, first fluid 112 and second fluid 116 flow through core 102in any of the following flow configurations, without limitation:counter-flow, parallel flow, cross-flow, and combinations thereof.Moreover, in some embodiments, first fluid 112 and second fluid 116 flowthrough core 102 in any of the following directions relative to eachother, without limitation: diagonal, curved, perpendicular, parallel,transverse, and combinations thereof.

Referring to FIGS. 1 and 2, a baffle 105 is used to guide the flows fromthe fluid supplies, e.g. the first fluid 112 and the second fluid 116,through the manifold portion 104, through the heat exchanger core 102,through the redirection portion 103, and out the fluid discharge areas126, 128. The baffle 105 is used to baffle both fluid domains at thesame location within the core 102 by interacting with both fluid domainswithin the same geometric plane. As discussed above, such an arrangementallows for a counter flow configuration, a parallel flow configuration,or a cross flow configuration. In such configurations, the flows of thefirst and second fluids are dependent on each other.

Referring to FIGS. 11-14, in an alternative embodiment a heat exchangercore 500 is formed by unit cells 108 in any manner similar to thatdescribed above. The heat exchanger core 500 may be provided in acasing, for example a casing 106 as described above, having a structuresimilar to that shown in FIGS. 1 and 2. The heat exchanger may alsoinclude manifold portions similar to those described above coupled tothe heat exchanger core 500. The manifold portions may each include aplurality of first inlets, second inlets, inlet headers, outlet headers,first outlets, and/or second outlets. The heat exchanger core 500 mayalso include an inlet plenum and an outlet plenum similar to the heatexchanger core discussed above with respect to FIGS. 1 and 2.

The heat exchanger core 500 includes internal baffles 502, 504, 506, 508that guide the flow through the heat exchanger core 500. The baffles maybe provided in the first passageways and/or the second passageways toindependently guide each of the first fluid flow and the second fluidflow. As used herein the terms “independent” and “independently” meanthat the design of the first fluid flow is not dependent on theparameters of the second fluid flow. Each of the first fluid flow andthe second fluid flow may have an independent flow configuration andvelocities to match up the heat transfer and pressure drop requirements.The flow requirements for each of the first fluid and the second fluidare determined by the flow rate, the pressure drop, the heat transfer,volume requirements, and/or internal baffle placement.

As shown in FIGS. 11-14, the baffles 502, 504, 506, 508 may be solidwalls built into the heat exchanger, for example the heat exchanger core500, that block the flow passages encompassed by the individual unitcells 108. The baffles may independently block the flow passages of aparticular fluid domain, e.g. the first fluid domain and/or the secondfluid domain, to route the fluid flow through the core 500 withoutaffecting the flow passages of any of the other fluid domains. Unlikethe baffle 105 shown in FIGS. 1 and 2, each baffle 502, 504, 506, 508 asshown in FIG. 14 blocks a flow passage of a particular fluid domain atits location without blocking the flow passage of any other fluid domainat the same location. As shown in FIG. 14, the baffles 502, 504, 506,508 allow the first fluid 112 to pass freely while blocking passage ofthe second fluid 116. Although it appears from the figure that the firstfluid 112 and the second fluid 116 cross or mix, it should beappreciated that the domains of the first fluid 112 and the second fluid116 are separate and no mixing of the first fluid 112 and the secondfluid 116 occurs.

The baffles may extend into each fluid's manifold region to provideimproved flow distribution and reduced pressure drop. If the inlet andoutlet locations for each fluid are in the same location independentbaffles can be used to provide partially or fully counterflow of thefluids, thus increasing the heat exchanger performance. This allows thepositions of the supply and discharge to be less limiting. A particularheat exchanger design may be limited by the required location of thesupply and discharge ports, the available volume, the flowrates pressuredrops, and required heat transfer. The use of the internal baffles toindependently route each fluid flow provides greater design freedom andresults in smaller, lighter, and better performing heat exchangers.

The systems and methods described herein include a core that enablesheat exchangers to have different shapes, sizes, and flowconfigurations. The core includes a plurality of unit cells. The unitcells define passageways for at least two different heat exchange fluidssuch that the fluids combine and divide in close proximity separatedonly by a sidewall of the unit cell. In some embodiments, each unit cellis configured to receive flows of heat exchange fluid from at leastthree other unit cells such that the flows combine into a single flow.In addition, each unit cell forms a trifurcated passageway portion suchthat the flow divides and is discharged into at least three other unitcells. As a result, the thermal boundary layers of the heat exchangefluids are reduced and the heat exchange fluids more efficientlytransfer heat through the sidewalls of the unit cells in comparison toheat exchange fluids in known heat exchangers. Moreover, the heatexchangers described herein include multiple arrangements and flowconfigurations to meet overall system requirements and have increasedefficiency.

This written description uses examples to disclose the embodiments,including the best mode, and to enable a person of ordinary skill in theart to practice the embodiments, including making and using any devicesor systems and performing any incorporated methods. The claims definethe patentable scope of the disclosure, and include other examples thatoccur to those of ordinary skill in the art. Such other examples areintended to be within the scope of the claims if they have structuralelements that do not differ from the literal language of the claims, orif they include equivalent structural elements with insubstantialdifferences from the literal language of the claims.

What is claimed is:
 1. A heat exchanger, comprising: a core defining afirst passageway configured for a first fluid to flow through and asecond passageway configured for a second fluid to flow through, thecore comprising an assembly comprised of a plurality of unit cellscoupled together, each unit cell of the assembly defining a firstpassageway portion within an interior volume of each unit cell and asecond passageway portion at an exterior surface of each unit cell, eachunit cell including a plurality of first openings into the interiorvolume for flow of the first fluid through the first passageway portion,wherein the assembly forms the second passageway in volumes between theplurality of unit cells coupled together, the assembly being shaped tocombine and divide the first fluid in the first passageway portion ineach unit cell and to combine and divide the second fluid in the secondpassageway portion of each unit cell during exchange of heat between thefirst fluid and the second fluid, and each second passageway portionreceives the second fluid from three other second passageway portions;and at least one baffle in at least one of the first passageway or thesecond passageway configured to route the flow of first fluidindependently from the flow of second fluid.
 2. The heat exchanger ofclaim 1, wherein the at least one baffle is configured to block thefirst passageway at its location without blocking the second passagewayat its location.
 3. The heat exchanger of claim 1, wherein the at leastone baffle is configured to block the second passageway at its locationwithout blocking the first passageway at its location.
 4. The heatexchanger of claim 1, further comprising: a casing, wherein the assemblyis configured to conform to a shape of the casing.
 5. The heat exchangerof claim 1, wherein the unit cells of the assembly are coupled in flowcommunication with each other such that each unit cell is configured toreceive the first fluid from at least three other unit cells.
 6. Theheat exchanger of claim 1, wherein one or more sidewalls of each unitcell has an at least partially curved shape such that the firstpassageway portion forms a blended flow passageway.
 7. The heatexchanger of claim 1, further comprising: a first header; and a secondheader, wherein the first fluid flows into the first passageway from thefirst header in a first direction and the second fluid flows into thesecond passageway from the second header in a second direction differentthan the first direction.
 8. The heat exchanger of claim 1, wherein thecore is substantially symmetric.
 9. The heat exchanger of claim 1,further comprising: a casing; and a peripheral unit cell adjacent thecasing, the peripheral unit cell configured to direct the first fluid ina direction away from the casing to inhibit the first fluid becomingtrapped in a stagnant zone.
 10. The heat exchanger of claim 1, furthercomprising; a first header coupled to the first passageway to direct thefirst fluid into the first passageway, the first header comprising aplurality of ports in flow communication with the first passageway andthe first header decreasing in cross-sectional area in the direction thefirst fluid flows through the first header.
 11. The heat exchanger ofclaim 10, wherein the core further defines a plenum for the second fluidto flow through, the plenum disposed adjacent the first header.
 12. Theheat exchanger of claim 10, further comprising: a plurality of conduitscoupled to the first header and extending adjacent the plenum.
 13. Theheat exchanger of claim 1, wherein each unit cell at least partiallydefines a first hydraulic diameter of the first passageway and a secondhydraulic diameter of the second passageway, the first hydraulicdiameter being different from the second hydraulic diameter.